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authorKarsten Graul <kgraul@linux.ibm.com>2020-04-30 15:55:38 +0200
committerDavid S. Miller <davem@davemloft.net>2020-04-30 12:44:33 -0700
commit555da9af827d95134656fa459c8f3ece04dd867a (patch)
treef2d35cfc1e42ad9d560cbc09855e8365240586c2 /net/smc/smc_llc.c
parent1569a3c44303834680e93df2ecf60f356be9b322 (diff)
net/smc: add event-based llc_flow framework
The new framework allows to start specific types of LLC control flows, protects active flows and makes it possible to wait for flows to finish before starting a new flow. This mechanism is used for the LLC control layer to model flows like 'add link' or 'delete link' which need to send/receive several LLC messages and are not allowed to get interrupted by the wrong type of messages. 'Add link' or 'Delete link' messages arriving in the middle of a flow are delayed and processed when the current flow finished. Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> Reviewed-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/smc/smc_llc.c')
-rw-r--r--net/smc/smc_llc.c165
1 files changed, 165 insertions, 0 deletions
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index e715dd6735ee..647cf1a2dfa5 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -140,6 +140,154 @@ struct smc_llc_qentry {
union smc_llc_msg msg;
};
+struct smc_llc_qentry *smc_llc_flow_qentry_clr(struct smc_llc_flow *flow)
+{
+ struct smc_llc_qentry *qentry = flow->qentry;
+
+ flow->qentry = NULL;
+ return qentry;
+}
+
+void smc_llc_flow_qentry_del(struct smc_llc_flow *flow)
+{
+ struct smc_llc_qentry *qentry;
+
+ if (flow->qentry) {
+ qentry = flow->qentry;
+ flow->qentry = NULL;
+ kfree(qentry);
+ }
+}
+
+static inline void smc_llc_flow_qentry_set(struct smc_llc_flow *flow,
+ struct smc_llc_qentry *qentry)
+{
+ flow->qentry = qentry;
+}
+
+/* try to start a new llc flow, initiated by an incoming llc msg */
+static bool smc_llc_flow_start(struct smc_llc_flow *flow,
+ struct smc_llc_qentry *qentry)
+{
+ struct smc_link_group *lgr = qentry->link->lgr;
+
+ spin_lock_bh(&lgr->llc_flow_lock);
+ if (flow->type) {
+ /* a flow is already active */
+ if ((qentry->msg.raw.hdr.common.type == SMC_LLC_ADD_LINK ||
+ qentry->msg.raw.hdr.common.type == SMC_LLC_DELETE_LINK) &&
+ !lgr->delayed_event) {
+ lgr->delayed_event = qentry;
+ } else {
+ /* forget this llc request */
+ kfree(qentry);
+ }
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ return false;
+ }
+ switch (qentry->msg.raw.hdr.common.type) {
+ case SMC_LLC_ADD_LINK:
+ flow->type = SMC_LLC_FLOW_ADD_LINK;
+ break;
+ case SMC_LLC_DELETE_LINK:
+ flow->type = SMC_LLC_FLOW_DEL_LINK;
+ break;
+ case SMC_LLC_CONFIRM_RKEY:
+ case SMC_LLC_DELETE_RKEY:
+ flow->type = SMC_LLC_FLOW_RKEY;
+ break;
+ default:
+ flow->type = SMC_LLC_FLOW_NONE;
+ }
+ if (qentry == lgr->delayed_event)
+ lgr->delayed_event = NULL;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ smc_llc_flow_qentry_set(flow, qentry);
+ return true;
+}
+
+/* start a new local llc flow, wait till current flow finished */
+int smc_llc_flow_initiate(struct smc_link_group *lgr,
+ enum smc_llc_flowtype type)
+{
+ enum smc_llc_flowtype allowed_remote = SMC_LLC_FLOW_NONE;
+ int rc;
+
+ /* all flows except confirm_rkey and delete_rkey are exclusive,
+ * confirm/delete rkey flows can run concurrently (local and remote)
+ */
+ if (type == SMC_LLC_FLOW_RKEY)
+ allowed_remote = SMC_LLC_FLOW_RKEY;
+again:
+ if (list_empty(&lgr->list))
+ return -ENODEV;
+ spin_lock_bh(&lgr->llc_flow_lock);
+ if (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
+ (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
+ lgr->llc_flow_rmt.type == allowed_remote)) {
+ lgr->llc_flow_lcl.type = type;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ return 0;
+ }
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ rc = wait_event_interruptible_timeout(lgr->llc_waiter,
+ (lgr->llc_flow_lcl.type == SMC_LLC_FLOW_NONE &&
+ (lgr->llc_flow_rmt.type == SMC_LLC_FLOW_NONE ||
+ lgr->llc_flow_rmt.type == allowed_remote)),
+ SMC_LLC_WAIT_TIME);
+ if (!rc)
+ return -ETIMEDOUT;
+ goto again;
+}
+
+/* finish the current llc flow */
+void smc_llc_flow_stop(struct smc_link_group *lgr, struct smc_llc_flow *flow)
+{
+ spin_lock_bh(&lgr->llc_flow_lock);
+ memset(flow, 0, sizeof(*flow));
+ flow->type = SMC_LLC_FLOW_NONE;
+ spin_unlock_bh(&lgr->llc_flow_lock);
+ if (!list_empty(&lgr->list) && lgr->delayed_event &&
+ flow == &lgr->llc_flow_lcl)
+ schedule_work(&lgr->llc_event_work);
+ else
+ wake_up_interruptible(&lgr->llc_waiter);
+}
+
+/* lnk is optional and used for early wakeup when link goes down, useful in
+ * cases where we wait for a response on the link after we sent a request
+ */
+struct smc_llc_qentry *smc_llc_wait(struct smc_link_group *lgr,
+ struct smc_link *lnk,
+ int time_out, u8 exp_msg)
+{
+ struct smc_llc_flow *flow = &lgr->llc_flow_lcl;
+
+ wait_event_interruptible_timeout(lgr->llc_waiter,
+ (flow->qentry ||
+ (lnk && !smc_link_usable(lnk)) ||
+ list_empty(&lgr->list)),
+ time_out);
+ if (!flow->qentry ||
+ (lnk && !smc_link_usable(lnk)) || list_empty(&lgr->list)) {
+ smc_llc_flow_qentry_del(flow);
+ goto out;
+ }
+ if (exp_msg && flow->qentry->msg.raw.hdr.common.type != exp_msg) {
+ if (exp_msg == SMC_LLC_ADD_LINK &&
+ flow->qentry->msg.raw.hdr.common.type ==
+ SMC_LLC_DELETE_LINK) {
+ /* flow_start will delay the unexpected msg */
+ smc_llc_flow_start(&lgr->llc_flow_lcl,
+ smc_llc_flow_qentry_clr(flow));
+ return NULL;
+ }
+ smc_llc_flow_qentry_del(flow);
+ }
+out:
+ return flow->qentry;
+}
+
/********************************** send *************************************/
struct smc_llc_tx_pend {
@@ -547,6 +695,16 @@ static void smc_llc_event_work(struct work_struct *work)
llc_event_work);
struct smc_llc_qentry *qentry;
+ if (!lgr->llc_flow_lcl.type && lgr->delayed_event) {
+ if (smc_link_usable(lgr->delayed_event->link)) {
+ smc_llc_event_handler(lgr->delayed_event);
+ } else {
+ qentry = lgr->delayed_event;
+ lgr->delayed_event = NULL;
+ kfree(qentry);
+ }
+ }
+
again:
spin_lock_bh(&lgr->llc_event_q_lock);
if (!list_empty(&lgr->llc_event_q)) {
@@ -676,6 +834,8 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
INIT_WORK(&lgr->llc_event_work, smc_llc_event_work);
INIT_LIST_HEAD(&lgr->llc_event_q);
spin_lock_init(&lgr->llc_event_q_lock);
+ spin_lock_init(&lgr->llc_flow_lock);
+ init_waitqueue_head(&lgr->llc_waiter);
lgr->llc_testlink_time = net->ipv4.sysctl_tcp_keepalive_time;
}
@@ -683,7 +843,12 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc)
void smc_llc_lgr_clear(struct smc_link_group *lgr)
{
smc_llc_event_flush(lgr);
+ wake_up_interruptible_all(&lgr->llc_waiter);
cancel_work_sync(&lgr->llc_event_work);
+ if (lgr->delayed_event) {
+ kfree(lgr->delayed_event);
+ lgr->delayed_event = NULL;
+ }
}
int smc_llc_link_init(struct smc_link *link)